An ultrastructural study of the synovial fluid (S.F.) in rheumatoid arthritis versus ankylotic spondylarthritis

Our studies focused on the cytomorphological and ultrastructural analysis of ten synovial fluid (S.F.) samples from patients with serum positive rheumatoid arthritis (R.A.) (latex 1/1280, 1/640 and Waaler-Rose 1/1024, 1/1512) as compared to five S.F. sampes from patients with peripheral ankylotic spondylarthritis (A.S.). The cytomorphological investigation aimed at defining the cellularity, ragocytosis and synoviocytogram. We found out that the average number of cells (R.A. = 8060/mm3; A.S. = 6100/mm3), percentage of ragocytes (R.A. = 75%; A.S. = 25%), polymorphonuclear cells (R.A. = 70%; A.S. = 58%), degradative polymorphonuclear cells (R.A. = 7%, A.S. = 3%) and phagocytic mononuclear cells (R.A. = 16%; A.S. = 13%) are by far larger in R.A. than in A.S., whereas the lymphocyte percentage is much more reduced (R.A. = 13%; A.S. = 26%). Ultrastructurally, the rheumatoid S.F. ragocytes present specific intracytoplasmic inclusions and phagolysosomes pointing to an endocytotic activity. At the level of the degradative polymorphonuclear cells (7% cytomorphologically confirmed), the alteration of the granular-fibrillar structure of the nucleus and the presence of some cytoplasmic lysis areas were associated with the absence of cellular organelles. We also noticed cellular and collagen detritus. In A.S. the ultrastructural effect on the polymorphonuclear cells is much more reduced (3%) as compared to R.A. and resides in the dilatation of both mitochondrial cristae and granularendoreticular cisternae as well as in a slight concentration of the fibrogranular nuclear matter. The cells are considerably active in endocytosis. The phagocytotic mononuclear cells of the rheumatoid S.F. and A.S. are morphologically identical to the immunologically activated macrophages.(ABSTRACT TRUNCATED AT 250 WORDS)